May 16, 2020

Aecom buys out rival URS in $4 billion deal

construction mergers
global acquisitions
US business deal
Admin
2 min
The buyout will see the emergence of a substantial conglomerate
Aecomand URS Corporation have announced an agreement under which Aecom will acquire all outstanding shares of URS for a combination of cash and stock va...

Aecom and URS Corporation have announced an agreement under which Aecom will acquire all outstanding shares of URS for a combination of cash and stock valued at approximately $4 billion.

Including the assumption of URS debt, the total enterprise value of the transaction is approximately $6 billion.

The combined company will be a leading, fully integrated infrastructure and federal services provider with more than 95,000 employees in 150 countries.  It would have calendar year 2013 pro forma revenues of more than $19 billion and earnings before insurance tax, depreciation and amortization of approximately $1.3 billion.

Michael S. Burke, Aecom president and Chief Executive Officer, said: “This combination creates an industry leader with the ability to deliver more capabilities from a broad global platform to reach more clients in more industry end markets.

“Clients, employees and stockholders of both companies will benefit from the opportunities created by these expanded capabilities and broad global reach in key growth markets and economies.  In one step, we will dramatically accelerate our strategy of creating an integrated delivery platform with superior capabilities to design, build, finance and operate infrastructure assets around the world.”

Martin M. Koffel, Chairman and Chief Executive Officer of URS, said: “This is a compelling strategic combination that we believe will benefit our clients, stockholders and employees.

“URS stockholders will receive significant, immediate value from the transaction and will be able to participate in the future prospects of the combined company, which we expect will be better positioned to compete for major, complex projects across a diverse range of end markets and geographic regions.”

Koffel continued, “Our two businesses are complementary, and our cultures are highly compatible.  We anticipate that employees from the combined company will benefit as the organization integrates its leadership talent and capitalizes on its greater scale to invest in its people, improve their career opportunities and advance their capacity to compete globally.”

Aecom will pay $56.31 per URS share, based on Aecom's closing price on July 11, 2014, representing a premium of 19% over the trailing 30-day average closing price of URS shares ending that day. URS stockholders will receive per share consideration equal to $33.00 in cash and 0.734 shares of Aecom common stock for each URS share.

Share article

Jun 17, 2021

Why engineers must always consider human-induced vibration

Vibrations
Engineering
design
Structuralintegrity
Dominic Ellis
3 min
Human-induced vibration can lead to a number of effects upon the structure and its users

Human induced vibration, or more accurately vibrations caused by human footfall, often conjures images of Millennium Bridge-style swaying or collapsing buildings.

But in reality, the ‘damage’ caused by human-induced vibrations is less likely to ruin a structure and more likely to cause discomfort in people. Though not as dramatic as a structural failure, any good engineer wants to make sure the people using their structures, be it bridges or buildings or anything in between, can do so safely and comfortably. This is why human-induced vibration must be considered within the design process.

Resonance v Impulse

There are two ways that human-induced vibrations affect structures: resonant, and impulse or transient response. Put simply, resonance occurs when Object A vibrates at the same natural frequency as Object B.

Object B resonates and begins to vibrate too. Think singing to break a wine glass! Although the person singing isn’t touching the glass, the vibrations of their voice are resonating with the glass’s natural frequency, causing this vibration to get stronger and stronger and eventually, break the glass. In the case of a structure, resonance occurs when the pedestrian’s feet land in time with the vibration.

On the other hand, impulse or transient vibration responses can be a problem on structures where its natural frequencies are too high for resonance to occur, such as where the structure is light or stiff. Here the discomfort is caused by the initial “bounce” of the structure caused by the footstep and is a concern on light or stiff structures.

Engineers must, of course, design to reduce the vibration effects caused by either impulse or resonance.

Potential impacts from human induced vibration

Human induced vibration can lead to a number of effects upon the structure and its users. These include:

  • Interfering with sensitive equipment Depending on the building’s purpose, what it houses can be affected by the vibrations of people using the building. Universities and laboratories, for example, may have sensitive equipment whose accuracy and performance could be damaged by vibrations. Even in ordinary offices the footfall vibration can wobble computer screens, upsetting the workers.
     
  • Swaying bridges One of the most famous examples of human-induced resonance impacting a structure occurred with the Millennium Bridge. As people walked across the bridge, the footsteps caused the bridge to sway, and everybody had to walk in time with the sway because it was difficult not to. Thankfully, this feedback can only occur with horizontal vibrations so building floors are safe from it, but footbridges need careful checking to prevent it.
     
  • Human discomfort According to research, vibrations in buildings and structures can cause depression and even motion sickness in inhabitants. Tall buildings sway in the wind and footsteps can be felt, even subconsciously by the occupants. It has been argued that modern efficient designs featuring thinner floor slabs and wider spacing in column design mean that these new builds are not as effective at dampening vibrations as older buildings are.
     
  • Jeopardising structural integrity The build-up of constant vibrations on a structure can, eventually, lead to structural integrity being compromised. A worse-case scenario would be the complete collapse of the structure and is the reason some bridges insist that marching troops break step before crossing. Crowds jumping in time to music or in response to a goal in a stadium are also dynamic loads that might damage an under-designed structure.

How to avoid it

As mentioned, modern designs that favour thinner slabs and wider column spacing are particularly susceptible to all forms of vibration, human-induced or otherwise, but short spans can also suffer due to their low mass. Using sophisticated structural engineering software is an effective method for engineers to test for and mitigate footfall and other vibrations at the design stage.

Share article